1. Field of the Invention
The present invention generally relates to computer apparatus and, in a preferred embodiment thereof, more particularly relates to pointing apparatus used to position a cursor on the display screen of a portable computer.
2. Description of Related Art
In portable computers, such as the increasingly popular notebook computer, a variety of cursor control or "pointing" devices have been utilized to position the cursor on the display screen portion of the computer. These devices include built-in and clip-on trackball structures, separate mouse devices, and devices known as "pointing sticks".
Unlike its trackball and mouse counterparts, which provide a ball-shaped element that must be rolled to effect the desired cursor movement on the display screen, a pointing stick is typically positioned between a pair of key caps on the computer keyboard and projects upwardly beyond their top side surfaces. To controllably move the cursor about the display screen the pointing stick is pushed generally parallel to the top side of the keyboard, about an appropriate horizontal axis. For example, if it is desired to move the cursor rightwardly on the screen, the pointing stick is rocked to the right and then released when the cursor reaches the desired new location on the screen. To effect the desired cursor movement built-in sensors in the overall pointing stick structure detect the direction in which the stick has been manually rocked, and the force with which it has been rocked, and responsively output a signal to the cursor control circuitry of the computer to move the cursor in the desired direction, and at the desired speed, respectively.
Conventionally constructed pointing sticks potentially offer several advantages over trackballs and mice. For example, the typical pointing stick is positioned on the keyboard in a manner such that it may be manipulated by the computer user without removing his hands from their "home key" touch typing position. Additionally, since the pointing stick is built into the computer there is no separate pointing device that must be connected to the computer during its use, and then disconnected when the computer is to be stored. Moreover, the pointing stick is quite compact in a horizontal direction, thereby permitting it to be readily incorporated in the keyboard of a modern notebook computer.
As conventionally constructed, however, pointing sticks of this general type tend to conflict with the design goal of minimizing the thickness of the modern notebook computer. Specifically, since the lid portion of a notebook computer typically closes onto the top sides of the keyboard key caps, and the top end of the pointing stick projects upwardly beyond the top sides of the key caps to enable the computer user to reach and manipulate the stick, it has heretofore been necessary to construct the lid in a manner such that it clears the pointing stick when closed. This, in turn, undesirably increases the overall thickness of the notebook computer in its closed storage and transport orientation.
As can readily be seen from the foregoing, it would be desirable to provide on a portable computer keyboard an improved pointing stick structure which maintains the accessibility and ease of use of a conventional pointing stick yet does not appreciably increase the overall thickness of its associated portable computer due to increased lid clearance requirements. It is accordingly an object of the present invention to provide a portable computer, such as a notebook computer, with improved pointing stick structure having these characteristics.